U.S. patent application number 10/566499 was filed with the patent office on 2006-09-28 for method for adhesive-bonding vulcanized rubber compositions by the use of thermoplastic elastomer compositions.
Invention is credited to Keisuke Chino, Takashi Kakubo.
Application Number | 20060213605 10/566499 |
Document ID | / |
Family ID | 34918285 |
Filed Date | 2006-09-28 |
United States Patent
Application |
20060213605 |
Kind Code |
A1 |
Kakubo; Takashi ; et
al. |
September 28, 2006 |
Method for adhesive-bonding vulcanized rubber compositions by the
use of thermoplastic elastomer compositions
Abstract
An object of the present invention is to provide a method of
adhering a vulcanized rubber composition using a thermoplastic
elastomer composition capable of maintaining recycling property and
excellent in adhesiveness. The above object is achieved by the
following method of adhering a vulcanized rubber composition. A
method of adhering a vulcanized rubber composition of the present
invention is a method of adhering a vulcanized rubber composition
using a thermoplastic elastomer composition. The thermoplastic
elastomer composition contains a thermoplastic elastomer and a
filler. The thermoplastic elastomer has: a monomer unit forming a
rubber component of the vulcanized rubber composition on at least
part of its main chain; and a side chain containing a structure
represented by a predetermined structural formula, the structure
having a carbonyl group and an imino group, and/or a
nitrogen-containing heterocyclic ring. The method includes adhering
a first member and a second member each composed of the vulcanized
rubber composition through the thermoplastic elastomer
composition.
Inventors: |
Kakubo; Takashi; (Kanagawa,
JP) ; Chino; Keisuke; (Kanagawa, JP) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER;LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Family ID: |
34918285 |
Appl. No.: |
10/566499 |
Filed: |
March 2, 2005 |
PCT Filed: |
March 2, 2005 |
PCT NO: |
PCT/JP05/03479 |
371 Date: |
January 31, 2006 |
Current U.S.
Class: |
156/110.1 |
Current CPC
Class: |
B29C 65/5057 20130101;
C08L 51/06 20130101; B29C 66/73941 20130101; B29C 66/71 20130101;
B29C 65/405 20130101; B29C 66/71 20130101; B29C 66/73756 20130101;
B29C 66/71 20130101; B29K 2101/12 20130101; B29K 2021/003 20130101;
C08F 8/30 20130101; B29C 66/71 20130101; C09J 123/16 20130101; B29K
2105/24 20130101; B29C 66/71 20130101; B29C 66/71 20130101; B29C
65/4815 20130101; C08L 51/04 20130101; B29C 65/425 20130101; C09J
123/16 20130101; C08L 23/16 20130101; B29K 2009/00 20130101; B29K
2007/00 20130101; B29K 2023/16 20130101; B29K 2019/00 20130101;
B29K 2021/00 20130101; B29K 2009/06 20130101; C08L 2666/24
20130101; C08L 2666/24 20130101; B29C 66/73754 20130101; B29C 66/71
20130101; B29K 2021/00 20130101 |
Class at
Publication: |
156/110.1 |
International
Class: |
B29C 35/00 20060101
B29C035/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 9, 2004 |
JP |
2004-065921 |
Claims
1. A method of adhering a vulcanized rubber composition using a
thermoplastic elastomer composition, wherein the thermoplastic
elastomer composition containing a thermoplastic elastomer and a
filler, and the thermoplastic elastomer having: a monomer unit
forming a rubber component of the vulcanized rubber composition on
at least part of its main chain; and a side chain containing a
structure represented by the following formula (1) and/or a
nitrogen-containing heterocyclic ring, the method comprising
adhering a first member and a second member each composed of the
vulcanized rubber composition through the thermoplastic elastomer
composition: ##STR12## (wherein A represents an alkyl group having
1 to 30 carbon atoms, an aralkyl group having 7 to 20 carbon atoms,
or an aryl group having 6 to 20 carbon atoms, and B represents: a
single bond; an oxygen atom, an amino group NR' (R' represents a
hydrogen atom or an alkyl group having 1 to 10 carbon atoms.), or a
sulfur atom; or an organic group which may contain any one of these
atoms or groups).
2. The method of adhering a vulcanized rubber composition according
to claim 1, wherein the adhesion is performed by: applying the
thermoplastic elastomer composition in a state of being molten to a
surface/surfaces of the first member and/or the second member to be
adhered; and subjecting a resultant to contact bonding.
3. The method of adhering a vulcanized rubber composition according
to claim 1, wherein the adhesion is performed by injecting or
extruding the thermoplastic elastomer composition in a state of
being molten into a space between the first member and the second
member.
4. The method of adhering a vulcanized rubber composition according
to claim 1, wherein the adhesion is performed by: sandwiching a
sheet-like product composed of the thermoplastic elastomer
composition between the surfaces of the first member and the second
member to be adhered; and subjecting a resultant to contact bonding
under heat at a temperature equal to or higher than a temperature
at which the sheet-like product melts.
5. The method of adhering a vulcanized rubber composition according
to any one of claims 1 to 4, wherein the side chain containing a
structure represented by the formula (1) contains a structure
represented by the following formula (2) or (3) that binds to a
main chain at a position .alpha. or .beta.: ##STR13## (wherein A
represents an alkyl group having 1 to 30 carbon atoms, an aralkyl
group having 7 to 20 carbon atoms, or an aryl group having 6 to 20
carbon atoms, and B and D each independently represent: a single
bond; an oxygen atom, an amino group NR' (R' represents a hydrogen
atom or an alkyl group having 1 to 10 carbon atoms.), or a sulfur
atom; or an organic group which may contain any one of these atoms
or groups).
6. The method of adhering a vulcanized rubber composition according
to claim 1, wherein the side chain containing a nitrogen-containing
heterocyclic ring contains a structure represented by the following
formula (4): ##STR14## [wherein E represents a nitrogen-containing
heterocyclic ring, and B represents: a single bond; an oxygen atom,
an amino group NR' (R' represents a hydrogen atom or an alkyl group
having 1 to 10 carbon atoms.), or a sulfur atom; or an organic
group which may contain any one of these atoms or groups].
7. The method of adhering a vulcanized rubber composition according
to claim 6, wherein the side chain containing a nitrogen-containing
heterocyclic ring contains a structure represented by the following
formula (5) or (6) that binds to a main chain at a position .alpha.
or .beta.: ##STR15## [wherein E represents a nitrogen-containing
heterocyclic ring, and B and D each independently represent: a
single bond; an oxygen atom, an amino group NR' (R' represents a
hydrogen atom or an alkyl group having 1 to 10 carbon atoms.), or a
sulfur atom; or an organic group which may contain any one of these
atoms or groups].
8. The method of adhering a vulcanized rubber composition according
to claim 1, wherein the nitrogen-containing heterocyclic ring
comprises a five- or six-membered ring.
9. The method of adhering a vulcanized rubber composition according
to claim 8, wherein the nitrogen-containing heterocyclic ring
comprises a triazole ring, a thiadiazole ring, a thiazole ring, a
pyridine ring, an imidazole ring, or a hydantoin ring.
10. The method of adhering a vulcanized rubber composition
according to claim 1, wherein the monomer unit forming a rubber
component of the vulcanized rubber composition has at least one
kind selected from the group consisting of ethylene, propylene,
isoprene, and butadiene, and has a unit similar to the at least one
kind on at least part of the main chain of the thermoplastic
elastomer.
11. The method of adhering a vulcanized rubber composition
according to claim 10, wherein: the rubber component of the
vulcanized rubber composition comprises an
ethylene-propylene-nonconjugated diene terpolymer (EPDM); and the
thermoplastic elastomer has an ethylene unit and a propylene unit
on at least part of its main chain.
12. The method of adhering a vulcanized rubber composition
according to claim 11, wherein an elastomeric polymer constituting
the main chain of the thermoplastic elastomer comprises an
ethylene-propylene copolymer (EPM) or an
ethylene-propylene-nonconjugated diene terpolymer (EPDM), or a
mixture of them.
13. The method of adhering a vulcanized rubber composition
according to claim 1, wherein a difference between an ethylene
content (mass %) of the rubber component of the vulcanized rubber
composition and an ethylene content (mass %) of the thermoplastic
elastomer is 25 mass % or less.
14. The method of adhering a vulcanized rubber composition
according to claim 1, wherein the thermoplastic elastomer
composition contains 1 to 100 parts by mass of the filler with
respect to 100 parts by mass of the thermoplastic elastomer.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method of adhering a
vulcanized rubber composition using a thermoplastic elastomer
composition.
BACKGROUND ART
[0002] In general, a rubber product such as a weather strip or a
glass run has been produced by: cutting an extruded vulcanized
molded product composed of a rubber composition; setting the cut
product into a die from one or both of the sides of the mold;
injecting a similar rubber molded material into a cavity; and
subjecting the resultant to vulcanization molding.
[0003] However, such vulcanization molding takes a long time to
vulcanize a vulcanized molded product and a similar rubber molded
material, and involves a problem, that is, the absence of recycling
property because an adhesion portion cannot be dismantled.
[0004] A method involving adhesion by means of a thermoplastic
elastomer without vulcanization molding has been known as a method
of solving such problem, and a known example of such thermoplastic
elastomer includes "a thermoplastic elastomer composition to be
used for forming a fused surface skin or fused molded product for a
vulcanized molded product composed of a rubber blend of an
ethylene-propylene-nonconjugated diene terpolymer (EPDM),
including: a thermoplastic elastomer; and an ethylene/1-octene
copolymer to be blended with the thermoplastic elastomer in an
amount of 5 to 45 parts by weight with respect to 100 parts by
weight of the thermoplastic elastomer, the thermoplastic elastomer
composition being characterized in that: the ethylene/1-octene
copolymer has an 1-octene content of 10 to 30 mass %; and the
molecular weight distribution M.sub.w/M.sub.n of the polymer is in
the range of 1.0 to 3.5'' (see Patent Document 1).
Patent Document 1: JP-A-09-40814
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0005] However, the adhesiveness of the thermoplastic elastomer
composition described in Patent Document 1 above may reduce because
its physical properties such as hardness, modulus, and
processability may be reduced by adding a filler or a
plasticizer.
[0006] Therefore, an object of the present invention is to provide
a method of adhering a vulcanized rubber composition using a
thermoplastic elastomer composition capable of maintaining
recycling property and excellent in adhesiveness.
Means to Solve the Problems
[0007] In view of the above, the inventors of the present invention
have made extensive studies to achieve the above object. As a
result, they have found that the use of a specific thermoplastic
elastomer composition for adhering members each composed of a
vulcanized rubber composition maintains recycling property and
provides excellent adhesiveness, thereby completing the present
invention. That is, the present invention provides a method of
adhering a vulcanized rubber composition using a thermoplastic
elastomer composition according to any one of the following items
(I) to (XIV).
[0008] (I) A method of adhering a vulcanized rubber composition
using a thermoplastic elastomer composition, the thermoplastic
elastomer composition containing a thermoplastic elastomer and a
filler, and the thermoplastic elastomer having: a monomer unit
forming a rubber component of the vulcanized rubber composition on
at least part of its main chain; and a side chain containing a
structure represented by the following formula (1) and/or a
nitrogen-containing heterocyclic ring, the method including
adhering a first member and a second member each composed of the
vulcanized rubber composition through the thermoplastic elastomer
composition. ##STR1##
[0009] In the formula, A represents an alkyl group having 1 to 30
carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an
aryl group having 6 to 20 carbon atoms, and B represents: a single
bond; an oxygen atom, an amino group NR' (R' represents a hydrogen
atom or an alkyl group having 1 to 10 carbon atoms.), or a sulfur
atom; or an organic group which may contain any one of these atoms
or groups.
[0010] (II) The method of adhering a vulcanized rubber composition
according to the above item (I), in which the adhesion is performed
by: applying the thermoplastic elastomer composition in a state of
being molten (a molten state) to the surface/surfaces of the first
member and/or the second member to be adhered; and subjecting the
resultant to contact bonding.
[0011] (III) The method of adhering a vulcanized rubber composition
according to the above item (I), in which the adhesion is performed
by injecting or extruding the thermoplastic elastomer composition
in a state of being molten into a space between the first member
and the second member.
[0012] (IV) The method of adhering a vulcanized rubber composition
according to the above item (I), in which the adhesion is performed
by: sandwiching a sheet-like product composed of the thermoplastic
elastomer composition between the surfaces of the first member and
the second member to be adhered; and subjecting the resultant to
contact bonding under heat at a temperature equal to or higher than
the temperature at which the sheet-like product melts.
[0013] (V) The method of adhering a vulcanized rubber composition
according to any one of the above items (I) to (IV), in which the
side chain containing a structure represented by the formula (1)
contains a structure represented by the following formula (2) or
(3) that binds to a main chain at a position .alpha. or .beta..
##STR2##
[0014] In the formula, A represents an alkyl group having 1 to 30
carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an
aryl group having 6 to 20 carbon atoms, and B and D each
independently represent: a single bond; an oxygen atom, an amino
group NR' (R' represents a hydrogen atom or an alkyl group having 1
to 10 carbon atoms.), or a sulfur atom; or an organic group which
may contain any one of these atoms or groups.
[0015] (VI) The method of adhering a vulcanized rubber composition
according to any one of the above items (I) to (V), in which the
side chain containing a nitrogen-containing heterocyclic ring
contains a structure represented by the following formula (4).
##STR3##
[0016] In the formula, E represents a nitrogen-containing
heterocyclic ring, and B represents: a single bond; an oxygen atom,
an amino group NR' (R' represents a hydrogen atom or an alkyl group
having 1 to 10 carbon atoms.), or a sulfur atom; or an organic
group which may contain any one of these atoms or groups.
[0017] (VII) The method of adhering a vulcanized rubber composition
according to the above item (VI), in which the side chain
containing a nitrogen-containing heterocyclic ring contains a
structure represented by the following formula (5) or (6) that
binds to a main chain at a position .alpha. or .beta.. ##STR4##
[0018] In the formula, E represents a nitrogen-containing
heterocyclic ring, and B and D each independently represent: a
single bond; an oxygen atom, an amino group NR' (R' represents a
hydrogen atom or an alkyl group having 1 to 10 carbon atoms.), or a
sulfur atom; or an organic group which may contain any one of these
atoms or groups.
[0019] (VIII) The method of adhering a vulcanized rubber
composition according to any one of the above items (I) to (VII),
in which the nitrogen-containing heterocyclic ring is a five- or
six-membered ring.
[0020] (IX) The method of adhering a vulcanized rubber composition
according to the above item (VIII), in which the
nitrogen-containing heterocyclic ring is a triazole ring, a
thiadiazole ring, a thiazole ring, a pyridine ring, an imidazole
ring, or a hydantoin ring.
[0021] (X) The method of adhering a vulcanized rubber composition
according to any one of the above items (I) to (IX), in which the
monomer unit forming a rubber component of the vulcanized rubber
composition is at least one kind selected from the group consisting
of ethylene, propylene, isoprene, and butadiene, and a unit similar
to the at least one kind is on at least part of the main chain of
the thermoplastic elastomer.
[0022] (XI) The method of adhering a vulcanized rubber composition
according to the above item (X), in which: the rubber component of
the vulcanized rubber composition is an
ethylene-propylene-nonconjugated diene terpolymer (EPDM); and the
thermoplastic elastomer has an ethylene unit and a propylene unit
on at least part of its main chain.
[0023] (XII) The method of adhering a vulcanized rubber composition
according to the above item (XI), in which an elastomeric polymer
constituting the main chain of the thermoplastic elastomer is an
ethylene-propylene copolymer (EPM) or an
ethylene-propylene-nonconjugated diene terpolymer (EPDM), or a
mixture of them.
[0024] (XIII) The method of adhering a vulcanized rubber
composition according to any one of the above items (I) to (XII),
in which a difference between the ethylene content (mass %) of the
rubber component of the vulcanized rubber composition and the
ethylene content (mass %) of the thermoplastic elastomer is 25 mass
% or less.
[0025] (XIV) The method of adhering a vulcanized rubber composition
according to any one of the above items (I) to (XIII), in which the
thermoplastic elastomer composition contains 1 to 100 parts by mass
of the filler with respect to 100 parts by mass of the
thermoplastic elastomer.
EFFECTS OF THE INVENTION
[0026] As described below, the present invention is useful because
the present invention can provide a method of adhering a vulcanized
rubber composition using a thermoplastic elastomer composition
capable of maintaining recycling property and excellent in
adhesiveness.
BEST MODE FOR CARRYING OUT THE INVENTION
[0027] Hereinafter, the present invention will be described in
detail.
[0028] A method of adhering a vulcanized rubber composition using a
thermoplastic elastomer composition of the present invention
(hereinafter simply referred to as the "adhesion method of the
present invention") is a method of adhering a vulcanized rubber
composition using a specific thermoplastic elastomer composition to
be detailed later, the method including adhering a first member and
a second member each composed of the vulcanized rubber composition
through the thermoplastic elastomer composition.
[0029] The adhesion method of the present invention involves the
utilization of not a solvent but a heat fusion phenomenon of a
thermoplastic elastomer composition.
[0030] Specific examples of a preferable method in the case where
at least one of the first member and the second member is not fixed
include: a method involving applying the thermoplastic elastomer
composition turned in a molten state by heating to the
surface/surfaces of the first member and/or the second member to be
adhered and subjecting the members to contact bonding; and a method
involving sandwiching a sheet-like product composed of the
thermoplastic elastomer composition between the surfaces of the
first member and the second member to be adhered and subjecting the
members to contact bonding under heat at the temperature at which
the sheet-like product melts.
[0031] Specific examples of a preferable method in the case where
the first member and the second member are fixed so as to be out of
contact with each other include: a method involving injecting or
extruding the thermoplastic elastomer composition turned in a
molten state by heating into a gap between the members and
subjecting the members to contact bonding after the injection or
extrusion as required; and a method involving inserting the
thermoplastic elastomer composition into a gap between the members
and subjecting the members to contact bonding under heating at the
temperature at which the thermoplastic elastomer composition
melts.
[0032] Any one of contact bonding, contact bonding under heating,
and injection can be adopted to favorably adhere the members
serving as adherends when the members each have a smooth surface
shape such as a sheet-like shape. On the other hand, when the
members each have a surface shape such as a complicated
convexo-concave shape, injection is preferably adopted because the
members can be adhered more easily than in the case of contact
bonding and an adhesion effect comparable to that of contact
bonding can be obtained. Therefore, the adhesion method of the
present invention preferably involves injection in various
situations where a vulcanized rubber composition is actually used
for producing parts (such as packings, window frames, and
hoses).
[0033] The term "contact bonding" as used herein refers to the
adhesion of the surfaces of the first and second members to be
adhered by means of pressing through the thermoplastic elastomer
composition, while the term "contact bonding under heating" as used
herein refers to the contact bonding while heating is
performed.
[0034] As described above, the term "injection" refers to a method
involving filling a gap between the first and second members with
the thermoplastic elastomer composition molten by heating in the
case where the members are fixed so as to be out of contact with
each other. The injection involves the use of means for adhering
the members at a sufficient injection pressure. The term "injection
pressure" refers to the pressure to be generated in a molding
machine for injecting a molten thermoplastic elastomer
composition.
[0035] In addition, the term "extrusion" refers to a method
involving filling a gap between the first and second members with
the thermoplastic elastomer composition molten by heating with the
aid of, for example, the rotation of a screw. The extrusion
involves the use of means for adhering the members at an extrusion
pressure at the time of extrusion.
[0036] In addition, a sheet-like product composed of the
thermoplastic elastomer composition, which is obtained by, for
example, the rolling of the thermoplastic elastomer composition,
has a thickness (sheet thickness) of 0.1 to 10 mm, or preferably
0.5 to 5 mm.
[0037] In the present invention, a pressing pressure at the time of
the contact bonding can be adjusted depending on the kind of
vulcanized rubber composition constituting each member. For
example, the contacting pressure is not particularly limited as
long as 1 kPa or more when the rubber component of the vulcanized
rubber composition is EPDM, and is preferably 0.1 MPa to 10
MPa.
[0038] In addition, in the present invention, the time required for
the contact bonding (contact bonding time) is not particularly
limited, but is preferably about 1 to 5 minutes in terms of
excellent workability and excellent adhesiveness.
[0039] In addition, in the present invention, the temperature
required for the contact bonding (contact bonding temperature) is
preferably 150 to 220.degree. C., or more preferably 180 to
200.degree. C. in terms of adhesion efficiency. It should be noted
that the heating involved in the contact bonding under heating,
that is, the temperature at which the sheet-like product composed
of the thermoplastic elastomer composition or the thermoplastic
elastomer melts is about 150 to 220.degree. C.
[0040] In the present invention, an injection pressure at the time
of the injection can be adjusted depending on the kind of
vulcanized rubber composition constituting each member. For
example, the injection pressure is not particularly limited as long
as 0.1 MPa or more when the rubber component of the vulcanized
rubber composition is EPDM, and is preferably 0.5 MPa to 10
MPa.
[0041] In addition, in the present invention, a pressure at the
time of the extrusion can be adjusted depending on the kind of
vulcanized rubber composition constituting each member. For
example, the pressure is not particularly limited as long as 0.1
MPa or more when the rubber component of the vulcanized rubber
composition is EPDM, and is preferably 0.5 MPa to 20 MPa.
[0042] Next, the vulcanized rubber composition and the
thermoplastic elastomer composition to be used for the adhesion
method of the present invention will be described in detail.
<Vulcanized Rubber Composition>
[0043] The vulcanized rubber composition to be used for the
adhesion method of the present invention is not particularly
limited as long as it is a vulcanized rubber composition obtained
by vulcanizing an unvulcanized rubber composition containing a
rubber component and a filler.
[0044] In the present invention, a monomer unit forming the rubber
component preferably has at least one kind selected from the group
consisting of ethylene, propylene, isoprene, and butadiene.
[0045] Specific examples of such rubber component include: diene
rubbers such as natural rubber (NR), isoprene rubber (IR),
butadiene rubber (BR), 1,2-butadiene rubber, styrene-butadiene
rubber (SBR), acrylonitrile-butadiene rubber (NBR), and EPDM, and
hydrogenated products of the rubbers; and olefin rubbers such as
EPM, ethylene-acrylic rubber (AEM), ethylene-butene rubber (EBM),
polyethylene rubber, and polypropylene rubber.
[0046] Of those, EPDM, EPM, and EBM are preferable, and EPDM is
more preferable.
[0047] In the present invention, each of the above rubber
components may be used alone, or two or more of them may be used in
combination. A mixing ratio when two or more of them are used in
combination can be an arbitrary ratio depending on, for example,
applications where the vulcanized rubber composition is used and
physical properties requested for the vulcanized rubber
composition.
[0048] Specific examples of the filler include carbon black,
silica, iron oxide, zinc oxide, aluminum oxide, titanium oxide,
barium oxide, magnesium oxide, calcium carbonate, magnesium
carbonate, zinc carbonate, agalmatolite clay, kaolin clay, and
calcined clay.
[0049] The content of the filler is not particularly limited, and
is 10 to 200 parts by mass, or preferably 50 to 120 parts by mass
with respect to 100 parts by mass of the rubber component as
required.
[0050] An unvulcanized rubber composition is generally vulcanized
by: adding a vulcanizer, and, as required, a vulcanization
assistant, a vulcanization accelerator, a vulcanization retardant,
and the like to the rubber composition; and heating the mixture to
120 to 200.degree. C., or preferably 140 to 190.degree. C., but a
method for the vulcanization is not particularly limited to this
method.
[0051] Examples of such vulcanizer include sulfur, organic
peroxide, and metal oxide vulcanizers, a phenol resin, and quinone
dioxime.
[0052] Specific examples of the sulfur vulcanizer include powdered
sulfur, precipitated sulfur, high-dispersible sulfur,
surface-treated sulfur, insoluble sulfur, dimorpholine disulfide,
and alkyl phenol disulfide.
[0053] Specific examples of the organic peroxide vulcanizer include
benzoyl peroxide, t-butylhydro peroxide, 2,4-dichlorobenzoyl
peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, and
2,5-dimethylhexane-2,5-di(peroxylbenzoate).
[0054] Other vulcanizers include magnesium oxide, litharge (lead
oxide), p-quinone dioxime, tetrachloro-p-benzoquinone, p-dibenzoyl
quinone dioxime, poly-p-dinitrosobenzene, and
methylenedianiline.
[0055] Specific examples of the vulcanization assistant include:
zinc oxide; magnesium oxide; amines; aliphatic acids such as acetic
acid, propionic acid, butanoic acid, stearic acid, acrylic acid,
and maleic acid; and zinc salts of aliphatic acids such as zinc
acetate, zinc propionate, zinc butanoate, zinc stearate, zinc
acrylate, and zinc maleate.
[0056] Specific examples of the vulcanization accelerator include:
thiuram vulcanization accelerators such as tetramethylthiuram
disulfide (TMTD) and tetraethylthiuram disulfide (TETD);
aldehyde-ammonia vulcanization accelerators such as
hexamethylenetetramine; guanidine vulcanization accelerators such
as diphenyl guanidine; thiazole vulcanization accelerators such as
2-mercaptobenzothiazole and dibenzothiazole disulfide (DM); and
sulfenamide vulcanization accelerators such as
N-cyclohexyl-2-benzothiazyl sulfenamide and
N-t-butyl-2-benzothiazyl sulfenamide. An alkyl phenol resin or a
halide thereof can also be used.
[0057] Specific examples of the vulcanization retardant
include:.organic acids such as phthalic anhydride, benzoic acid,
salicylic acid, and acetylsalicylic acid; nitroso compounds such as
polymers of N-nitroso-diphenylamine,
N-nitroso-phenyl-.beta.-naphthylamine, and
N-nitroso-trimethyl-dihydroquinoline; halides such as
trichlormelanine; 2-mercaptobenzimidazole; and
N-(cyclohexylthio)phthalimide (Santoguard PVI).
[0058] The total content of the vulcanizer, vulcanization
assistant, vulcanization accelerator, vulcanization retardant, and
the like is not particularly limited, but is preferably 0.1 to 20
parts by mass, or more preferably 1 to 10 parts by mass with
respect to 100 parts by mass of the unvulcanized rubber
composition.
<Thermoplastic Elastomer Composition>
[0059] The thermoplastic elastomer composition to be used for the
adhesion method of the present invention is a composition
containing a thermoplastic elastomer and a filer to be described
later, and contains 1 to 100 parts by mass, or preferably 5 to 50
parts by mass of the filler with respect to 100 parts by mass of
the thermoplastic elastomer. A content of the filler in the above
range is preferable because the adhesion method of the present
invention for which a thermoplastic elastomer composition to be
obtained is used provides good adhesiveness and improves a strength
after adhesion. A content of the filler in the above range is
preferable because the rubber physical properties (including
hardness and modulus) of the thermoplastic elastomer composition to
be obtained can be easily adjusted.
[0060] Hereinafter, the thermoplastic elastomer and the filler
constituting the thermoplastic elastomer composition will be
described in detail.
[0061] The thermoplastic elastomer constituting the thermoplastic
elastomer composition has: a unit similar to the monomer unit
forming the rubber component of the vulcanized rubber composition
on at least part of an elastomeric polymer of a natural polymer or
of a synthetic polymer forming a main chain; and a side chain
containing a structure represented by the formula (1) and/or a
nitrogen-containing heterocyclic ring.
[0062] The term "side chain" as used herein refers to any one of
the side chains and terminals of an elastomeric polymer. In
addition, the phrase "having a side chain containing a structure
represented by the formula (1) and/or a nitrogen-containing
heterocyclic ring" refers to a state where at least one of the
structure represented by the formula (1) and the
nitrogen-containing heterocyclic ring forms a chemically stable
bond (such as a covalent bond or an ionic bond) with an atom
(generally a carbon atom) forming the main chain of the elastomeric
polymer.
[0063] The elastomeric polymer serving as the main chain of the
thermoplastic elastomer is not particularly limited as long as it
is a generally known natural polymer or synthetic polymer, has a
glass transition point of room temperature (25.degree. C.) or lower
(that is, the elastomeric polymer is an elastomer), and has the
monomer unit forming the rubber component of the vulcanized rubber
composition on at least part thereof.
[0064] As in the case of the rubber component of the vulcanized
rubber composition described above, specific examples of such
elastomeric polymer include: diene rubbers such as NR, IR, BR,
1,2-butadiene rubber, SBR, NBR, and EPDM, and hydrogenated products
of the rubbers; and olefin rubbers such as EPM, AEM, EBM,
polyethylene rubber, and polypropylene rubber.
[0065] Of those, each of EPM and EPDM each having an ethylene unit
and a propylene unit is preferable because it provides the
thermoplastic elastomer and the thermoplastic elastomer composition
(which may hereinafter be simply referred to as the "thermoplastic
elastomer (composition)") with good heat resistance and good
weatherability.
[0066] The elastomeric polymer may also be an elastomeric polymer
containing a resin component, and specific examples of such polymer
include polystyrene elastomeric polymers (such as SBS, SIS, and
SEBS), polyolefin elastomeric polymers, polyvinyl chloride
elastomeric polymers, polyurethane elastomeric polymers, polyester
elastomeric polymers, and polyamide elastomeric polymers which may
be hydrogenated.
[0067] Furthermore, the elastomeric polymer may be a liquid or a
solid, and its molecular weight is not particularly limited and may
be appropriately selected depending on, for example, applications
where the thermoplastic elastomer (composition) are used and
physical properties requested for the elastomer and the elastomer
composition.
[0068] The elastomeric polymer is preferably a liquid when emphasis
is placed on the fluidity upon heating (decrosslinking) of the
thermoplastic elastomer (composition). For example, a diene rubber
such as isoprene rubber or butadiene rubber has a weight average
molecular weight of preferably 1,000 to 100,000, or more preferably
about 1,000 to 50,000.
[0069] The elastomeric polymer is preferably a solid when emphasis
is placed on the strength of the thermoplastic elastomer
(composition). For example, a diene rubber such as isoprene rubber
or butadiene rubber has a weight average molecular weight of
preferably 100,000 or more, or more preferably about 500,000 to
1,500,000.
[0070] In the present invention, the weight average molecular
weight is a weight average molecular weight (in terms of
polystyrene) measured by means of gel permeation chromatography
(GPC). Tetrahydrofuran (THF) is preferably used for the measurement
as a solvent.
[0071] In the present invention, two or more kinds of the
elastomeric polymers may be used as a mixture. A mixing ratio of
the respective elastomeric polymers in this case can be an
arbitrary ratio depending on, for example, applications where the
thermoplastic elastomer (composition) are used and physical
properties requested for the thermoplastic elastomer
(composition).
[0072] As described above, the glass transition point of the
elastomeric polymer is preferably 25.degree. C. or lower. When the
elastomeric polymer has two or more glass transition points or when
two or more kinds of the elastomeric polymers are used as a
mixture, at least one of the glass transition points is preferably
25.degree. C. or lower. A glass transition point of the elastomeric
polymer in the above range is preferable because a molded product
composed of the thermoplastic elastomer (composition) shows
rubber-like elasticity at room temperature.
[0073] In the present invention, the glass transition point is a
glass transition point measured by means of differential scanning
calorimetry (DSC). A rate of temperature increase is preferably set
to 10.degree. C./min.
[0074] In the present invention, for example, the amount of bound
styrene in the styrene-butadiene rubber (SBR) and the hydrogenation
ratio of the elastomeric polymer or the like are not particularly
limited, and can be adjusted to arbitrary values depending on, for
example, applications where the thermoplastic elastomer
(composition) are used and physical properties requested for the
thermoplastic elastomer (composition).
[0075] The thermoplastic elastomer has a side chain containing a
structure represented by the following formula (1) and/or a
nitrogen-containing heterocyclic ring on the elastomeric polymer.
##STR5##
[0076] In the formula, A represents an alkyl group having 1 to 30
carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an
aryl group having 6 to 20 carbon atoms, and B represents: a single
bond; an oxygen atom, an amino group NR' (R' represents a hydrogen
atom or an alkyl group having 1 to 10 carbon atoms.), or a sulfur
atom; or an organic group which may contain any one of these atoms
or groups.
[0077] The substituent A is not particularly limited as long as it
is any one of the above-described alkyl group having 1 to 20 carbon
atoms, aralkyl group having 7 to 20 carbon atoms, and aryl group
having 6 to 20 carbon atoms.
[0078] Specific examples of such substituent A include: linear
alkyl groups such as a methyl group, an ethyl group, a propyl
group, a butyl group, a pentyl group, an octyl group, a dodecyl
group, and a stearyl group; branched alkyl groups such as an
isopropyl group, an isobutyl group, an s-butyl group, a t-butyl
group, an isopentyl group, a neopentyl group, a t-pentyl group, a
1-methylbutyl group, a 1-methylheptyl group, and a 2-ethylhexyl
group; aralkyl groups such as a benzyl group and a phenethyl group;
and aryl groups such as a phenyl group, an (o-, m-, or p-) tolyl
group, a dimethylphenyl group, and a mesityl group.
[0079] Of those, an alkyl group, especially a butyl group, an octyl
group, a dodecyl group, an isopropyl group, or a 2-ethylhexyl group
is preferable because the processability of the thermoplastic
elastomer (composition) to be obtained becomes good.
[0080] The substituent B is not particularly limited as long as it
is: a single bond; an oxygen atom, an amino group NR' (R'
represents a hydrogen atom or an alkyl group having 1 to 10 carbon
atoms.), or a sulfur atom; or an organic group which may contain
any one of these atoms or groups.
[0081] Specific examples of such substituent B include: a single
bond; an oxygen atom, a sulfur atom, or an amino group NR' (R'
represents a hydrogen atom or an alkyl group having 1 to 10 carbon
atoms); an alkylene or aralkylene group having 1 to 20 carbon atoms
which may contain any one of these atoms or groups; an alkylene
ether (alkylene oxy group such as a --O--CH.sub.2CH.sub.2-- group),
alkylene amino (such as a --NH--CH.sub.2CH.sub.2-- group), or
alkylene thioether group (alkylene thio group such as a
--S--CH.sub.2CH.sub.2-- group) having 1 to 20 carbon atoms, the
group having any one of these atoms or groups at a terminal
thereof; and an aralkylene ether (aralkylene oxy group), aralkylene
amino, or aralkylene thioether group having 1 to 20 carbon atoms,
the group having any one of these atoms or groups at a terminal
thereof.
[0082] Examples of the alkyl group having 1 to 10 carbon atoms in
the amino group NR' include a methyl group, an ethyl group, a
propyl group, a butyl group, a pentyl group, a hexyl group, a
heptyl group, an octyl group, a nonyl group, and a decyl group
including their isomers.
[0083] An oxygen atom, a sulfur atom, and an amino group NR' of the
substituent B, and an oxygen atom, an amino group NR', and a sulfur
atom of an alkylene ether, alkylene amino, alkylene thioether,
aralkylene ether, aralkylene amino, or aralkylene thioether group
having 1 to 20 carbon atoms, the group having any one of these
atoms or groups at a terminal thereof, are preferably combined with
adjacent carbonyl groups to form conjugate ester, amide, imide,
thioester, and like other groups.
[0084] Of those, the substituent B is preferably: an oxygen atom, a
sulfur atom, or an amino group; or an alkylene ether, alkylene
amino, or alkylene thioether group having 1 to 20 carbon atoms, the
group having any one of these atoms or groups at a terminal
thereof, and is particularly preferably an amino group (NH), an
alkylene amino group (a --NH--CH.sub.2-- group, a
--NH--CH.sub.2CH.sub.2-- group, or a
--NH--CH.sub.2CH.sub.2CH.sub.2-- group), or an alkylene ether group
(a --O--CH.sub.2-- group, a --O--CH.sub.2CH.sub.2-- group, or a
--O--CH.sub.2CH.sub.2CH.sub.2-- group)
[0085] The thermoplastic elastomer preferably has the side chain
containing the structure represented by the formula (1) as a side
chain containing a structure represented by the following formula
(2) or (3) that binds to a main chain at a position .alpha. or
.beta.. ##STR6##
[0086] In the formula, A represents an alkyl group having 1 to 30
carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an
aryl group having 6 to 20 carbon atoms, and B and D each
independently represent: a single bond; an oxygen atom, an amino
group NR' (R' represents a hydrogen atom or an alkyl group having 1
to 10 carbon atoms.), or a sulfur atom; or an organic group which
may contain any one of these atoms or groups.
[0087] Here, the substituent A is basically identical to the
substituent A in the formula (1), and the substituents B and D are
each independently identical to the substituent B in the formula
(1).
[0088] It should be noted that the substituent D in the formula (3)
is preferably: a single bond; or one forming a conjugate system
with imide nitrogen of an alkylene or aralkylene group having 1 to
20 carbon atoms which may contain an oxygen atom, an amino group
NR', or a sulfur atom out of those exemplified for the substituent
B in the formula (1), and is particularly preferably an alkylene
group. That is, the substituent D preferably forms an alkylene
amino or aralkylene amino group (particularly preferably, an
alkylene amino group) having 1 to 20 carbon atoms which may contain
an oxygen atom, an amino group NR', or a sulfur atom with the imide
nitrogen in the formula (3).
[0089] Specific examples of such substituent D include: a single
bond; an alkylene ether, alkylene amino, alkylene thioether,
aralkylene ether, aralkylene amino, or aralkylene thioether group
having 1 to 20 carbon atoms, the group having any one of the
above-described oxygen atom, sulfur atom, and amino group at a
terminal thereof; and a methylene, ethylene, propylene, butylene,
hexylene, phenylene, or xylylene group including an isomer
thereof.
[0090] The side chain containing a structure represented by any one
of the formulae (1), (2), and (3) is preferably introduced at a
rate (introduction rate) of 0.1 to 50 mol % with respect to 100 mol
% of a monomer constituting the elastomeric polymer. A rate of less
than 0.1 mol % may provide insufficient strength at the time of
crosslinking, while a rate in excess of 50 mol % may increase a
crosslink density to lose rubber elasticity. When the introduction
rate is in the above range, an intermolecular or intramolecular
interaction between side chains of the elastomeric polymer occurs,
so the structures are formed in a balanced manner. As a result, the
tensile strength of the thermoplastic elastomer (composition) to be
obtained at the time of crosslinking is high, so excellent
adhesiveness, excellent recycling property, and a good compression
set can be obtained. The side chain is introduced at a rate of more
preferably 0.1 to 30 mol %, or still more preferably 0.5 to 20 mol
% because those properties become more excellent.
[0091] Furthermore, as described above, the thermoplastic elastomer
has a side chain containing a nitrogen-containing heterocyclic ring
instead of or in addition to a side chain containing a structure
represented by any one of the formulae (1), (2), and (3).
[0092] In the present invention, the nitrogen-containing
heterocyclic ring is introduced in the main chain of the
elastomeric polymer directly or through an organic group.
[0093] The nitrogen-containing heterocyclic ring may contain a
hetero atom except a nitrogen atom such as a sulfur atom, an oxygen
atom, or a phosphorus atom in a heterocyclic ring as long as it
contains a nitrogen atom in the heterocyclic ring. Here, a
heterocyclic compound is used because the presence of a
heterocyclic ring structure strengthens a hydrogen bond for forming
a crosslink, so the tensile strength of the thermoplastic elastomer
(composition) to be obtained increases to provide excellent
adhesiveness.
[0094] In addition, the nitrogen-containing heterocyclic ring may
have a substituent, and specific examples of the substituent
include: an alkyl group such as a methyl group, an ethyl group, an
(iso)propyl group, or a hexyl group; an alkoxy group such as a
methoxy group, an ethoxy group, or an (iso)propoxy group; a group
composed of a halogen atom such as a fluorine atom, a chlorine
atom, a bromine atom, or an iodine atom; a cyano group; an amino
group; an aromatic hydrocarbon group; an ester group; an ether
group; an acyl group; and a thioether group. Those groups may be
used in combination. The substitution positions of those
substituents are not particularly limited, and the number of
substituents is not limited either.
[0095] Furthermore, the nitrogen-containing heterocyclic ring may
or may not have aromaticity, but preferably has aromaticity because
the tensile strength of the thermoplastic elastomer (composition)
to be obtained at the time of crosslinking additionally increases
to additionally improve adhesiveness.
[0096] The nitrogen-containing heterocyclic ring is preferably a
five-membered or six-membered ring.
[0097] Specific examples of such nitrogen-containing heterocyclic
ring include pyrrololine, pyrrolidone, oxyindole (2-oxyindole),
indoxyl (3-oxyindole), dioxyindole, isatin, indolyl, phthalimidine,
.beta.-isoindigo, monoporphyrin, diporphyrin, triporphyrin,
azaporphyrin, phthalocyanine, hemoglobin, uroporphyrin,
chlorophyll, phylloerythrine, imidazole, pyrazole, triazole,
tetrazole, benzimidazole, benzopyrazole, benzotriazole,
imidazoline, imidazolone, imidazolidone, hydantoin, pyrazoline,
pyrazolone, pyrazolidone, indazole, pyridoindole, purine,
cinnoline, pyrrole, pyrroline, indole, indoline, oxylindole,
carbazole, phenothiazine, indolenine, isoindole, oxazole, thiazole,
isoxazole, isothiazole, oxadiazole, thiadiazole, oxatriazole,
thiatriazole, phenanthroline, oxazine, benzoxazine, phthalazine,
pteridine, pyrazine, phenazine, tetrazine, benzoxazole,
benzoisoxazole, anthranil, benzothiazole, benzofurazan, pyridine,
quinoline, isoquinoline, acridine, phenanthridine, anthrazoline,
naphthyridine, thiazine, pyridazine, pyrimidine, quinazoline,
quinoxaline, triazine, histidine, triazolidine, melamine, adenine,
guanine, thymine, cytosine, and derivatives of them. Of those,
preferable examples of the nitrogen-containing five-membered ring
include the following compounds, an imidazole derivative
represented by the following formula (7), and a triazole derivative
represented by the following formula (8). Each of those rings may
have any one of the above-described various substituents, or
hydrogen may be added to or eliminated from the ring. ##STR7##
[0098] In the formulae, the substituent X is an alkyl group having
1 to 30 carbon atoms, an aralkyl group having 7 to 20 carbon atoms,
or an aryl group having 6 to 20 carbon atoms, and is basically
identical to the substituent A in the formula (1).
[0099] Preferable examples of the nitrogen-containing six-membered
ring include the following compounds. Each of those compounds may
have any one of the above-described various substituents, or
hydrogen may be added to or eliminated from the compound.
##STR8##
[0100] A product as a result of condensation between the
nitrogen-containing heterocyclic ring and a benzene ring or between
nitrogen-containing heterocyclic rings may also be used. Specific
preferable examples thereof include the following condensed rings.
Each of those condensed rings may have any one of the
above-described various substituents, or a hydrogen atom may be
added to or eliminated from the condensed ring. ##STR9##
[0101] Of such nitrogen-containing heterocyclic rings, a triazole
ring, a pyridine ring, a thiazole ring, a thiadizole ring, an
imidazole ring, or a hydantoin ring is preferable because the
recycling property, compression set, mechanical strength, and
hardness of the thermoplastic elastomer (composition) to be
obtained are excellent.
[0102] When the thermoplastic elastomer has the side chain
containing the nitrogen-containing heterocyclic ring, it preferably
has the side chain as a side chain containing a structure
represented by the following formula (4), or more preferably has
the side chain as a side chain containing a structure represented
by the following formula (5) or (6) that binds to a main chain at a
position .alpha. or .beta.. ##STR10##
[0103] In the formula, E represents a nitrogen-containing
heterocyclic ring, and B and D each independently represent: a
single bond; an oxygen atom, an amino group NR' (R' represents a
hydrogen atom or an alkyl group having 1 to 10 carbon atoms.), or a
sulfur atom; or an organic group which may contain any one of these
atoms or groups.
[0104] Specific examples of the nitrogen-containing heterocyclic
ring E include the nitrogen-containing heterocyclic rings
exemplified above.
[0105] In addition, the substituents B and D are each independently
identical to the substituent B in the formula (1).
[0106] It should be noted that the substituent D in the formula (6)
is preferably: a single bond; or one forming a conjugate system
with imide nitrogen of an alkylene or aralkylene group having 1 to
20 carbon atoms which may contain an oxygen atom, an amino group
NR', or a sulfur atom, and is particularly preferably a single
bond. That is, the substituent D preferably forms an alkylene amino
or aralkylene amino group having 1 to 20 carbon atoms which may
contain an oxygen atom, an amino group NR', or a sulfur atom with
the imide nitrogen in the formula (6), and it is particularly
preferable that a nitrogen-containing heterocyclic ring directly
bind to the imide nitrogen in the formula (6) (single bond).
[0107] The side chain containing a containing a nitrogen-containing
heterocyclic ring is preferably introduced at a rate (introduction
rate) of 0.1 to 50 mol % with respect to 100 mol % of a monomer
constituting the elastomeric polymer. When the thermoplastic
elastomer has the side chain containing a nitrogen-containing
heterocyclic ring in addition to the side chain containing a
structure represented by any one of the formulae (1), (2), and (3),
in all, the side chain containing a nitrogen-containing
heterocyclic ring and the side chain containing a structure
represented by any one of the formulae (1), (2), and (3) are
preferably introduced at a total rate (introduction rate) of 0.1 to
50 mol % with respect to 100 mol % of the monomer constituting the
elastomeric polymer. An introduction ratio of those side chains
(the side chain containing a nitrogen-containing heterocyclic
ring/the side chain containing a structure represented by any one
of the formulae (1), (2), and (3)) is more preferably 1/99 to 99/1,
or still more preferably 10/90 to 90/10.
[0108] The introduction rate and the introduction ratio are
preferably within the above ranges because mechanical strength such
as tensile strength can be additionally improved and the staining
of the thermoplastic elastomer (composition) resulting from the
nitrogen-containing heterocyclic ring to be introduced can be
suppressed while the property described in the paragraph [0062],
that is, the property in which "the tensile strength at the time of
crosslinking is high, so excellent adhesiveness, excellent
recycling property, and a good compression set can be obtained" is
maintained.
[0109] The thermoplastic elastomer preferably has a glass
transition point of 25.degree. C. or lower. When the thermoplastic
elastomer has two or more glass transition points or when two or
more kinds of thermoplastic elastomers are used in combination, at
least one of the glass transition points is preferably 25.degree.
C. or lower. A glass transition point of 25.degree. C. or lower
causes a molded product composed to show rubber-like elasticity at
room temperature.
[0110] A method of producing the thermoplastic elastomer is not
particularly limited, and any one of the ordinary methods can be
selected. To be specific, a preferable production method includes
the step of causing a compound capable of introducing an imino
group to react with an elastomeric polymer containing a cyclic acid
anhydride group at a side chain thereof (hereinafter simply
referred to as the "reaction step A").
[0111] In addition, when the thermoplastic elastomer has the side
chain containing a nitrogen-containing heterocyclic ring instead of
the side chain containing a structure represented by any one of the
formulae (1), (2), and (3), the method of producing the
thermoplastic elastomer is preferably a production method including
the step of causing a compound capable of introducing a
nitrogen-containing heterocyclic ring to react with an elastomeric
polymer containing a cyclic acid anhydride group at a side chain
thereof (hereinafter simply referred to as the "reaction step
B").
[0112] Furthermore, when the thermoplastic elastomer has the side
chain containing a nitrogen-containing heterocyclic ring in
addition to the side chain containing a structure represented by
any one of the formulae (1), (2), and (3), the method of producing
the thermoplastic elastomer is preferably a production method
including the reaction step A and the reaction step B. In this
case, the method may include the reaction step B as a step to be
performed simultaneously with the reaction step A. Alternatively,
the method may include the reaction step B as a step to be
performed prior to or after the reaction step A. However, the
method preferably includes the reaction step B as a step to be
performed prior to the reaction step A.
[0113] The term "elastomeric polymer containing a cyclic acid
anhydride group at a side chain thereof" as used herein refers to
an elastomeric polymer in which an cyclic acid anhydride group
forms a chemically stable bond (a covalent bond) with an atom
forming the main chain of the elastomeric polymer. Such elastomeric
polymer is obtained by causing the above elastomeric polymer and a
compound capable of introducing a cyclic acid anhydride group to
react with each other.
[0114] Specific examples of the compound capable of introducing a
cyclic acid anhydride group include cyclic acid anhydrides such as
succinic anhydride, maleic anhydride, glutaric anhydride, and
phthalic anhydride.
[0115] The elastomeric polymer containing a cyclic acid anhydride
group at a side chain thereof may be produced by means of a method
to be generally performed (for example, a method involving causing
a cyclic acid anhydride to undergo graft polymerization with the
above elastomeric polymer under typical conditions (such as
stirring under heating)), or may be a commercial product.
[0116] Examples of the commercial product include: maleic
anhydride-modified isoprene rubber such as LIR-403 (manufactured by
KURARAY CO., LTD.) or LIR-410A (a prototype of KURARAY CO., LTD.);
modified isoprene rubber such as LIR-410 (manufactured by KURARAY
CO., LTD.); carboxy-modified nitrile rubber such as Crinack 110,
221, or 231 (manufactured by Polyser Co., Ltd.); carboxy-modified
polybutene such as CPIB (manufactured by Nippon Petrochemicals Co.,
Ltd.) or HRPIB (a prototype of the laboratory of Nippon
Petrochemicals Co., Ltd.); maleic anhydride-modified
ethylene-propylene rubber such as Nucrel (manufactured by DU
PONT-MITSUI POLYCHEMICALS CO., LTD.), Yukaron (manufactured by
Mitsubishi Chemical Corporation), or Toughmer M (such as MA8510
(manufactured by Mitsui Chemicals, Inc.)); maleic
anhydride-modified ethylene-butene rubber such as Toughmer M (such
as MH7020 (manufactured by Mitsui Chemicals, Inc.)); maleic
anhydride-modified polyethylene such as ADTX series (such as maleic
anhydride-modified EVA or maleic anhydride-modified EMA
(manufactured by Nippon Polyolefin)) HPR series (such as maleic
anhydride-modified EEA or maleic anhydride-modified EVA
(manufactured by DU PONT-MITSUI POLYCHEMICALS CO., LTD.)), Bondfast
series (maleic anhydride-modified EMA (manufactured by Sumitomo
Chemical Co., Ltd.)), Dumilan series (maleic anhydride-modified
EVOH (manufactured by Takeda Pharmaceutical Company Limited)),
Bondine (maleic anhydride-modified EEA (manufactured by ATOFINA)),
Tuftec (maleic anhydride-modified SEBS, M1943 (manufactured by
Asahi Kasei Corporation)), Kraton (maleic anhydride-modified SEBS,
FG1901X (manufactured by Kraton Polymer)), Toughprene (maleic
anhydride-modified SBS, 912 (manufactured by Asahi Kasei
Corporation)), Septon (maleic anhydride-modified SEPS (manufactured
by KURARAY CO., LTD.)), Lexpearl (maleic anhydride-modified EEA,
ET-182G, 224M, or 234M (manufactured by Nippon Polyolefin)), or
Auroren (maleic anhydride-modified EEA, 200S or 250S (manufactured
by NIPPON PAPER CHEMICALS CO.,LTD.); and maleic anhydride-modified
polypropylene (such as QB550 or LF128 (manufactured by Mitsui
Chemicals, Inc.).
[0117] The compound capable of introducing an imino group is not
particularly limited as long as it is a compound having an imino
group not constituting part of a cyclic compound such as a
heterocyclic ring and any other active hydrogen group (such as a
hydroxyl group, a thiol group, or an amino group) in a molecule,
and specific examples thereof include: alkyl aminoalcohols such as
N-methylmethanolamine, N-ethylethanolamine, N-n-propylethanolamine,
N-n-butylethanolamine, N-n-pentylethanolamine,
N-n-hexylethanolamine, N-n-heptylethanolamine,
N-n-octylethanolamine, N-n-nonylethanolamine,
N-n-decylethanolamine, N-n-undecylethanolamine,
N-n-dodecylethanolamine, N-(2-ethylhexyl)ethanolamine,
N-methylaminopropanol, and N-methylaminobutanol; aromatic
aminoalcohols such as N-phenylaminoethanol, N-toluilaminoethanol,
N-phenylaminopropanol, and N-phenylaminobutanol; alkyl aminothiols
such as N-methylaminoethanethiol, N-ethylaminoethanethiol,
N-n-propylaminoethanethiol, N-n-butylaminoethanethiol,
N-methylaminopropanethiol, and N-methylaminobutanethiol; aromatic
aminothiols such as N-phenylaminoethanethiol,
N-toluilaminoethanethiol, N-phenylaminopropanethiol, and
N-phenylaminobutanethiol; alkyl diamines such as
N-methylethylenediamine, N-ethylethylenediamine,
N-n-propylethylenediamine, N-methylpropanediamine,
N-ethylpropanediamine, N-methylbutanediamine,
N,N'-dimethylethylenediamine, and N,N'-diethylethylenediamine; and
aromatic diamines such as N-phenylethylenediamine,
N-phenylpropanediamine, N-phenylbutanediamine, and
N,N'-diphenylethylenediamine.
[0118] Of those, N-n-butylethanolamine, N-n-octylethanolamine, or
N-n-dodecylethanolamine is preferable.
[0119] The reaction step A is a step involving: mixing a compound
capable of introducing an imino group and the elastomeric polymer
containing a cyclic acid anhydride group at a side chain thereof;
causing them to react with each other (subjecting the cyclic acid
anhydride group to ring-opening) at the temperature at which the
compound and the cyclic acid anhydride group chemically bind to
each other (for example, 80 to 200.degree. C.). The reaction allows
the thermoplastic elastomer to be obtained to contain a structure
represented by the formula (2) or (3) at a side chain thereof.
[0120] The compound capable of introducing an imino group may be
caused to react the part or whole of the cyclic acid anhydride
groups present at the side chains of the elastomeric polymer. The
term "part" means preferably 1 mol % or more, more preferably 50
mol % or more, or particularly preferably 80 mol % or more with
respect to 100 mol % of the cyclic acid anhydride groups. With the
range, high physical properties (such as breaking property) are
sufficiently exerted. The whole of the cyclic acid anhydride groups
(100 mol %) are particularly preferably caused to react with the
compound capable of introducing an imino group because an excellent
compressive set can be obtained.
[0121] The compound capable of introducing a nitrogen-containing
heterocyclic group may be any one of the nitrogen-containing
heterocyclic rings themselves exemplified above, or may be a
nitrogen-containing heterocyclic ring having a substituent (such as
a hydroxyl group, a thiol group, or an amino group) capable of
reacting with a cyclic acid anhydride group such as maleic
anhydride.
[0122] The reaction step B is a step involving: mixing a compound
capable of introducing a nitrogen-containing heterocyclic ring and
the elastomeric polymer containing a cyclic acid anhydride group at
a side chain thereof; causing them to react with each other
(subjecting the cyclic acid anhydride group to ring-opening) at the
temperature at which the compound and the cyclic acid anhydride
group chemically bind to each other (for example, 80 to 200.degree.
C.). The reaction allows the thermoplastic elastomer to be obtained
to contain a structure represented by the formula (5) or (6) at a
side chain thereof.
[0123] In addition, as described above, the reaction step B is
preferably a step to be performed prior to the reaction step A when
the method includes both the reaction step A and the reaction step
B. In this case, the compound capable of introducing a
nitrogen-containing heterocyclic ring may be caused to react part
of the cyclic acid anhydride groups present at the side chains of
the elastomeric polymer. The term "part" means preferably 1 to 99
mol %, more preferably 1 to 90 mol %, or particularly preferably 50
to 90 mol % with respect to 100 mol % of the cyclic acid anhydride
groups. With the range, an effect of introducing the
nitrogen-containing heterocyclic ring is exerted, and mechanical
strength such as tensile strength at the time of crosslinking is
additionally improved.
[0124] In the above production method, the respective groups
(structures) at the side chains of the thermoplastic elastomer,
that is, an unreacted cyclic acid anhydride group, and the
structures each represented by any one of the formulae (2), (3),
(5), and (6) can be identified by means of analysis means to be
generally used such as NMR or IR spectrum.
[0125] The bonding position of the nitrogen-containing heterocyclic
ring when the thermoplastic elastomer has the side chain containing
the nitrogen-containing heterocyclic ring will be described. The
nitrogen-containing heterocyclic ring is represented as a
"nitrogen-containing n-membered compound (n.gtoreq.3)" for
convenience.
[0126] The bonding position ("any one of the positions 1 to n") to
be described later is based on the IUPAC nomenclature system. For
example, in the case of a compound having three nitrogen atoms each
having an unshared electron pair, the bonding position is
determined depending on a rank based on the IUPAC nomenclature
system. To be specific, the bonding position is shown in the
nitrogen-containing heterocyclic ring of any one of the
five-membered, six-membered, and condensed rings exemplified
above.
[0127] In the thermoplastic elastomer, the bonding position of a
nitrogen-containing n-membered compound that binds to a copolymer
directly or through an organic group is not particularly limited,
and any one of the bonding positions (positions 1 to n) can be
adopted. The bonding site is preferably any one of the position 1
and the positions 3 to n.
[0128] When a nitrogen-containing compound contains one nitrogen
atom (for example, a pyridine ring), a chelate tends to be formed
in a molecule, so physical properties such as tensile strength when
the compound is provided as a composition become excellent.
Accordingly, the position is preferably any one of the positions 3
to (n-1).
[0129] Selecting the bonding position of the nitrogen-containing
n-membered compound tends to allow a crosslink due to a hydrogen
bond, ion bond, coordination bond, or the like to be formed between
molecules of the thermoplastic elastomer. Therefore, excellent
recycling property and excellent mechanical properties can be
obtained.
[0130] In the present invention, each of such thermoplastic
elastomers may be used alone, or two or more of them may be used in
combination. A mixing ratio when two or more of them are used in
combination can be an arbitrary ratio depending on, for example,
applications where the thermoplastic elastomer composition is used
and physical properties requested for the thermoplastic elastomer
composition.
[0131] As in the case of the vulcanized rubber composition
described above, specific examples of the filler constituting the
thermoplastic elastomer composition include carbon black, silica,
iron oxide, zinc oxide, aluminum oxide, titanium oxide, barium
oxide, magnesium oxide, calcium carbonate, magnesium carbonate,
zinc carbonate, agalmatolite clay, kaolin clay, and calcined
clay.
[0132] Of those, carbon black and/or silica are/is preferably
used.
[0133] The kind of carbon black is appropriately selected depending
on applications. In general, carbon blacks are classified into hard
carbon and soft carbon depending on particle sizes. The soft carbon
shows low reinforcing property on rubber, while the hard carbon
shows high reinforcing property on rubber. In the present
invention, the hard carbon showing high reinforcing property is
particularly preferably used.
[0134] Silica is not particularly limited, and specific examples
thereof include fumed silica, calcined silica, precipitated silica,
pulverized silica, molten silica, and diatomaceous earth.
[0135] When silica is used as the filler, a silane coupling agent
can be used in combination therewith. Examples of the silane
coupling agent include bis(triethoxysilylpropyl)tetrasulfide
(Si69), bis(triethoxysilylpropyl)disulfide (Si75),
.gamma.-mercaptopropyltrimethoxysilane, and vinyltrimethoxysilane.
An aminosilane coupling agent to be described later can also be
used.
[0136] As described above, the content of such filler is 1 to 100
parts by mass, or preferably 5 to 50 parts by mass with respect to
100 parts by mass of the thermoplastic elastomer. The content of
the filler is not limited to the above range when a softener (such
as paraffin oil, process oil, a petroleum resin, or vegetable oil)
is used because the content can be additionally increased.
[0137] In the present invention, the thermoplastic elastomer
composition may contain any one of various additives as required to
the extent that the object of the present invention is not
impaired. Examples of the additives include: a polymer except the
above thermoplastic elastomer; a filler having an amino group
introduced thereinto (hereinafter simply referred to as the "amino
group-introduced filler"); an amino group-containing compound
except the amino group-introduced filler; a compound containing a
metal element (hereinafter simply referred to as the "metal salt");
a maleic anhydride-modified polymer; an age inhibitor; an
antioxidant; a pigment (dye); a plasticizer; a thixotropy imparting
agent; a UV absorber; a flame retardant; a solvent; a surfactant
(including a leveling agent); a dispersant; a dehydrating agent; a
rust inhibitor; an adhesiveness imparting agent; an antistatic
agent; and a filler.
[0138] The above additives may be those generally used, and
specific examples thereof include, but not limited to, the
following additives.
[0139] The polymer except the above thermoplastic elastomer is
preferably a polymer having a glass transition point of 25.degree.
C. or lower by reason of the foregoing. Specific examples thereof
include NR, IR, BR, 1,2-butadiene rubber, SBR, NBR, IIR, EPDM, EPM,
AEM, and EBM. In particular, a polymer having no unsaturated bond
such as IIR, EPM, or EBM, or a polymer having a small amount of
unsaturated bond (such as EPDM) is preferable. A polymer having a
site that can form a hydrogen bond is also preferable, and examples
thereof include polyester, polylactone, and polyamide.
[0140] One or two or more kinds of the polymers except the above
thermoplastic elastomer may be incorporated into the thermoplastic
elastomer composition, and the (total) content of the polymer(s) is
preferably 0.1 to 100 parts by mass, or more preferably 1 to 50
parts by mass with respect to 100 parts by mass of the
thermoplastic elastomer.
[0141] Examples of a filler to serve as a base substance for the
amino group-introduced filler (which may hereinafter be simply
referred to as the "filler to serve as a base substance") include
the fillers exemplified above as fillers that can be added to the
vulcanized rubber as desired. Silica, carbon black, or calcium
carbonate is preferable in terms of the ease with which an amino
group is introduced and the ease with which the adjustment or the
like of an introduction rate (introduction rate) is performed, and
silica is more preferable.
[0142] An amino group to be introduced into the filler to serve as
a base substance (which may hereinafter be simply referred to as
the "amino group") is not particularly limited, and specific
examples thereof include an aliphatic amino group, an aromatic
amino group, an amino group constituting a heterocyclic ring, and a
mixed amino group containing multiple of these amino groups.
[0143] Here, in the present invention, an amino group possessed by
an aliphatic amine compound is referred to as an aliphatic amino
group, an amino group bound to an aromatic group possessed by an
aromatic amine compound is referred to as an aromatic amino group,
and an amino group possessed by a heterocyclic amine compound is
referred to as a heterocyclic amino group.
[0144] Of those, a heterocyclic amino group, a mixed amino group
containing a heterocyclic amino group, or an aliphatic amino group
is preferable because it can appropriately interact with the
thermoplastic elastomer to be effectively dispersed into the
thermoplastic elastomer, and a heterocyclic amino group or an
aliphatic amino group is more preferable.
[0145] The amino group may be any one of the primary (--NH.sub.2),
secondary (an imino group or >NH), tertiary (>N--), and
quaternary (>N.sup.+<) amino groups without any particular
limitation.
[0146] When the amino group is a primary amino group, an
interaction with the thermoplastic elastomer tends to be strong, so
the elastomer may be gelled depending on, for example, the
conditions under which a composition is prepared. On the other
hand, when the amino group is a tertiary amino group, an
interaction with the thermoplastic elastomer tends to be weak, so
an improving effect on a compression set or the like is small when
the elastomer is provided as a composition.
[0147] From such viewpoint, the amino group is preferably a primary
or secondary amino group, and is more preferably a secondary amino
group.
[0148] That is, the amino group is preferably a heterocyclic amino
group, a mixed amino group containing a heterocyclic amino group,
or a primary or secondary aliphatic amino group, and is
particularly preferably a heterocyclic amino group or a primary or
secondary aliphatic amino group.
[0149] The filler to serve as a base substance has only to have at
least one such amino group on its surface, but preferably has
multiple such amino groups because an excellent improving effect on
a compression set or the like can be obtained when a composition is
prepared.
[0150] When the filler to serve as a base substance has multiple
such amino groups, at least one of the multiple amino groups is
preferably a heterocyclic amino group, and the filler more
preferably has a primary or secondary amino group (aliphatic,
aromatic, or heterocyclic amino group).
[0151] The kind and grade of the amino group can be arbitrarily
adjusted depending on physical properties requested for a
composition.
[0152] The amino group-introduced filler can be obtained by
introducing the amino group into the filler to serve as a base
substance.
[0153] A method of introducing the amino group is not particularly
limited, and specific examples thereof include surface treatment
methods (such as a surface modification method and a surface
coating method) to be generally used for various fillers,
reinforcing agents, and the like. Examples of a preferable method
include: a method causing a compound having a functional group
capable of reacting with the filler to serve as a base substance
and the amino group to react with the filler (a surface
modification method); a method involving coating the surface of the
filler to serve as a base substance with a polymer having the amino
group (a surface coating method); and a method involving causing,
for example, a compound having the amino group to react in the
course of the synthesis of the filler.
[0154] Each of such amino group-introduced fillers may be used
alone, or two or more of them may be used in combination. A mixing
ratio when two or more of them are used in combination can be an
arbitrary ratio depending on, for example, applications where the
thermoplastic elastomer composition is used and physical properties
requested for the thermoplastic elastomer composition.
[0155] The content of the amino group-introduced filler(s) is
preferably 1 to 200 parts by mass, more preferably 10 parts by mass
or more, or particularly preferably 30 parts by mass or more with
respect to 100 parts by mass of the thermoplastic elastomer
composition.
[0156] Description will be given of the amino group-containing
compound except the amino group-introduced filler.
[0157] An amino group in the amino group-containing compound is
basically identical to that described with regard to the amino
group-introduced filler. In addition, the number of amino groups in
the compound is not particularly limited as long as the number is 1
or more, and is preferably 2 or more because the compound can form
2 or more crosslinkages with the thermoplastic elastomer to provide
excellent improving effects on physical properties.
[0158] As in the case of the amino group in the amino
group-introduced filler described above, the amino group in the
amino group-containing compound may be any one of the primary
(--NH.sub.2), secondary (an imino group or >NH), tertiary
(>N--), and quaternary (>N.sup.+<) amino groups without
any particular limitation, and any one of the primary to quaternary
amino groups can be selected depending on physical properties (such
as recycling property, a compression set, mechanical strength, and
hardness) requested for the thermoplastic elastomer composition.
When a secondary amino group is selected, mechanical strength tends
to be excellent. When a tertiary amino group is selected, recycling
property tends to be excellent. In particular, the amino
group-containing compound preferably has two secondary amino groups
because the recycling property and compression set of the
thermoplastic elastomer composition to be obtained are excellent
and a balance between both the physical properties is also
excellent.
[0159] When the amino group-containing compound contains 2 or more
amino groups, the number of primary amino groups in the amino
group-containing compound is preferably 2 or less, or more
preferably 1 or less. When the compound has 3 or more primary amino
groups, bonds (crosslinkages) to be formed by the amino groups and
the functional groups (especially a carboxy group as a
carbonyl-containing group) in the thermoplastic elastomer become
strong, so excellent recycling property is impaired in some
cases.
[0160] In other words, the grades and number of amino groups, and
the structure of the amino group-containing compound can be
appropriately adjusted and selected in consideration of, for
example, a bonding force between a functional group in the
thermoplastic elastomer and an amino group in the amino
group-containing compound.
[0161] Specific preferable examples of such amino group-containing
compound include: a secondary aliphatic diamine such as
N,N'-dimethylethylenediamine, N,N'-diethylethylenediamine,
N,N'-diisopropylethylenediamine, N,N'-dimethyl-1,3-propanediamine,
N,N'-diethyl-1,3-propanediamine,
N,N'-diisopropyl-1,3-propanediamine,
N,N'-dimethyl-1,6-hexanediamine, N,N'-diethyl-1,6-hexanediamine, or
N,N',N''-trimethylbis(hexamethylene)triamine; a tertiary aliphatic
diamine such as tetramethyl-1,6-hexanediamine; a polyamine
containing an aromatic primary amine and a heterocyclic amine such
as aminotriazole or aminopyridine; a linear alkyl monoamine such as
dodecylamine; and a tertiary heterocyclic diamine such as
dipyridyl. Each of them has high improving effects on a compression
set, mechanical strength, and the like.
[0162] Of those, a secondary aliphatic diamine, a polyamine
containing an aromatic primary amine and a heterocyclic amine, or a
tertiary heterocyclic diamine is more preferable.
[0163] Except those exemplified above, a high molecular weight
compound having an amino group can be used as the amino
group-containing compound.
[0164] The high molecular weight compound having an amino group is
not particularly limited, and specific examples thereof include:
polymers such as polyamide, polyurethane, a urea resin, a melamine
resin, polyvinylamine, polyallylamine, polyacrylamide,
polymethacrylamide, polyaminostyrene, and amino group-containing
polysiloxane; and polymers obtained by denaturing various with
compounds each having an amino group.
[0165] The average molecular weight, molecular weight distribution,
and physical properties such as viscosity of each of those polymers
are not particularly limited, and can be arbitrary ones depending
on, for example, applications where the thermoplastic elastomer
composition is used and physical properties requested for the
thermoplastic elastomer composition.
[0166] In addition, the high molecular weight compound having an
amino group is preferably a polymer obtained through the
polymerization (polyaddition or polycondensation) of a condensable
or polymerizable compound (monomer) having an amino group, and is
more preferably polysiloxane having an amino group as a
homopolycondensate of a silyl compound having a hydrolyzable
substituent and an amino group or as a copolycondensate of the
silyl compound and a silyl compound having no amino group because
it is readily available and can be easily produced, and its
molecular weight, its introduction ratio of an amino group, and the
like can be easily adjusted.
[0167] The silyl compound having a hydrolyzable substituent and an
amino group is not particularly limited, and an example thereof
includes an amihosilane compound. Specific examples thereof
include: an aminosilane compound having an aliphatic primary amino
group such as .gamma.-aminopropyltrimethoxysilane,
.gamma.-aminopropyltriethoxysilane,
.gamma.-aminopropylmethyldimethoxysilane,
.gamma.-aminopropylmethyldiethoxysilane, or
4-amino-3,3-dimethylbutyltrimethoxysilane (each of which is
manufactured by Nippon Unicar Co., Ltd.); an aminosilane compound
having an aliphatic secondary amino group such as
N,N-bis[(3-trimethoxysilyl)propyl]amine,
N,N-bis((3-triethoxysilyl)propyl]amine,
N,N-bis[(3-tripropoxysilyl)propyl]amine (each of which is
manufactured by Nippon Unicar Co., Ltd.),
3-(n-butylamino)propyltrimethoxysilane [Dynasilane 1189
(manufactured by Daicel-Degussa Ltd.)], or
N-ethyl-aminoisobutyltrimethoxysilane (Silquest A-Link 15 silane,
manufactured by OSi Specialities, Inc.); an aminosilane compound
having aliphatic primary and secondary amino groups such as
N-.beta.(aminoethyl).gamma.-aminopropylmethyldimethoxysilane,
N-.beta.(aminoethyl).gamma.-aminopropyltrimethoxysilane, or
N-.beta.(aminoethyl).gamma.-aminopropyltriethoxysilane
(manufactured by Nippon Unicar Co., Ltd.); an aminosilane compound
having an aromatic secondary amino group such as
N-phenyl-.gamma.-aminopropyltrimethoxysilane (manufactured by
Nippon Unicar Co., Ltd.); and imidazoletrimethoxysilane
(manufactured by JAPAN ENERGY CORPORATION) or an aminosilane
compound having a heterocyclic amino group such as triazolesilane
obtained by causing or aminotriazole and an epoxysilane compound,
an isocyanatesilane compound, or the like to react with each other
in the presence or absence of a catalyst at a temperature equal to
or higher than room temperature.
[0168] Of those, an aminoalkylsilane compound of any one of the
above-described aminosilane compound having an aliphatic primary
amino group, aminosilane compound having an aliphatic secondary
amino group, and aminosilane compound having aliphatic primary and
secondary amino groups is preferable because it has high improving
effects on physical properties such as a compression set.
[0169] The silyl compound having no amino group is not particularly
limited as long as it is a compound different from the silyl
compound having a hydrolyzable substituent and an amino group and
contains no amino group, and specific examples thereof include an
alkoxysilane compound and a halogenated silane compound. Of those,
an alkoxysilane compound is preferable because it is readily
available, can be easily handled, and provides a copolycondensate
to be obtained with excellent physical properties.
[0170] Specific examples of the alkoxysilane compound include
tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane,
tetraisopropoxysilane, methyltrimethoxysilane,
methyltriethoxysilane, methyltributoxysilane,
methyltriisopropoxysilane, phenyltrimethoxysilane, and
dimethyldimethoxysilane.
[0171] Specific examples of the halogenated silane compound include
tetrachlorosilane and vinyltrifluorosilane.
[0172] Of those, tetraethoxysilane or tetramethoxysilane is
preferable because, for example it is inexpensive and can be safely
handled.
[0173] One kind of silyl compound having a hydrolyzable substituent
and an amino group or of silyl compound having no amino group may
be used alone, or two or more kinds thereof may be used in
combination.
[0174] One of such high molecular weight compounds each having an
amino group may be used alone, or two or more of them may be used
in combination. A mixing ratio when two or more of them are used in
combination can be an arbitrary ratio depending on, for example,
applications where the thermoplastic elastomer composition is used
and physical properties requested for the thermoplastic elastomer
composition.
[0175] In addition, as in the case of the amino group-containing
compound, the content of the high molecular weight compound having
an amino group can be specified depending on the number of nitrogen
atoms (equivalents) in the compound with respect to a side chain of
the thermoplastic elastomer. However, in some cases, an amino group
is present, which is unable to effectively interact with the
thermoplastic elastomer depending on the structure, molecular
weight, and the like of the polymer compound.
[0176] Accordingly, the content of the high molecular weight
compound having an amino group is preferably 1 to 200 parts by
mass, more preferably 5 parts by mass or more, or particularly
preferably 10 parts by mass or more with respect to 100 parts by
mass of the thermoplastic elastomer.
[0177] The metal salt is not particularly limited as long as it is
a compound containing at least one metal element, and is preferably
a compound containing one or more kinds of metal elements selected
from the group consisting of Li, Na, K, Ti, V, Cr, Mn, Fe, Co, Ni,
Cu, Zn, Ga, and Al.
[0178] Specific examples of the metal salt include a saturated
aliphatic acid salt having 1 to 20 carbon atoms (such as a formate,
an acetate, or a stearate), an unsaturated aliphatic acid salt such
as (meth)acrylate, a metal alkoxide (a reactant with an alcohol
having 1 to 12 carbon atoms), a nitrate, a carbonate, a
bicarbonate, a chloride, an oxide, a hydroxide, and a complex with
a diketone each containing one or more kinds of those metal
elements.
[0179] The term "complex with a diketone" as used herein refers to
a complex in which 1,3-diketone (such as acetylacetone) or the like
coordinates with a metal atom.
[0180] Of those, Ti, Al, or Zn is a preferable metal element
because it additionally improves the compression set of the
thermoplastic elastomer composition to be obtained. The metal salt
is preferably the saturated aliphatic acid salt having 1 to 20
carbon atoms (such as an acetate or a stearate), metal alkoxide (a
reactant with an alcohol having 1 to 12 carbon atoms), oxide,
hydroxide, or complex with a diketone of any such metal element,
and is particularly preferably the saturated aliphatic acid salt
having 1 to 20 carbon atoms (such as a stearate), metal alkoxide (a
reactant with an alcohol having 1 to 12 carbon atoms), or complex
with a diketone thereof.
[0181] One of such metal salts may be used alone, or two or more of
them may be used in combination. A mixing ratio when two or more of
them are used in combination can be an arbitrary ratio depending
on, for example, applications where the thermoplastic elastomer
composition is used and physical properties requested for the
thermoplastic elastomer composition.
[0182] The content of the metal salt(s) is preferably 0.05 to 1.5
equivalents, more preferably 0.1 to 1.0 equivalent, or particularly
preferably 0.2 to 1.0 equivalent with respect to a carbonyl group
present in the thermoplastic elastomer. The content of the metal
salt is preferably within the range because the physical properties
(such as a compression set, mechanical strength, and hardness) of
the thermoplastic elastomer composition to be obtained are
improved.
[0183] In addition, the metal salt may be, for example, any one of
all possible hydroxides, metal alkoxides, and carboxylates of a
certain metal. For example, when iron is used as the metal, each of
its hydroxides, that is, Fe(OH).sub.2 and Fe(OH).sub.3 may be used
alone, or they may be used in combination.
[0184] Furthermore, as described above, the metal salt is
preferably a compound containing one or more kinds of metal
elements selected from the group consisting of Li, Na, K, Ti, V,
Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, and Al, but may contain a metal
element except these elements to the extent that an effect of the
present invention is not impaired. The content of the metal element
except those elements is not particularly limited, but is, for
example, preferably 1 to 50 mol % with respect to all metal
elements in the metal salt.
[0185] The term "maleic anhydride-modified polymer" refers to a
polymer obtained by denaturing the elastomeric polymer with maleic
anhydride. The maleic anhydride-modified polymer may have a maleic
anhydride residue and a functional group except a
nitrogen-containing heterocyclic ring at side chains thereof, but
preferably has only a maleic anhydride residue.
[0186] The side chain or terminal of the elastomeric polymer has
the maleic anhydride residue introduced thereinto (modified
therewith), and the residue is not introduced into the main chain
of the elastomeric polymer. In addition, the maleic anhydride
residue is a cyclic acid anhydride group, and its cyclic acid
anhydride group (portion) does not undergo ring-opening.
[0187] Therefore, an example of the maleic anhydride-modified
thermoplastic polymer includes a thermoplastic elastomer having a
cyclic acid anhydride group at a side chain thereof and having no
nitrogen-containing heterocyclic ring obtained through a reaction
between an ethylenically unsaturated bond portion of maleic
anhydride and an elastomeric polymer as shown in the following
formula (9). Specific examples of such thermoplastic elastomer
include the carbonyl-containing group-modified elastomers
exemplified above. ##STR11## (In the formula, G represents an
ethylene residue or a propylene residue, and l, m, and n each
independently represent a number of 0.1 to 80.)
[0188] The amount of maleic anhydride with which elastomeric
polymer is modified is preferably 0.1 to 50 mol %, more preferably
0.3 to 30 mol %, or particularly preferably 0.5 to 10 mol % with
respect to 100 mol % of the main chain portion of the elastomeric
polymer because a compression set can be improved without any
impairment of excellent recycling property.
[0189] Each of such maleic anhydride-modified polymers may be used
alone, or two or more of them may be used in combination. A mixing
ratio when two or more of them are used in combination can be an
arbitrary ratio depending on, for example, applications where the
thermoplastic elastomer composition is used and physical properties
requested for the thermoplastic elastomer composition.
[0190] The content of the maleic anhydride-modified polymer is
preferably 1 to 100 parts by mass, or more preferably 5 to 50 parts
by mass with respect to 100 parts by mass of the thermoplastic
elastomer. The content of the maleic anhydride-modified polymer is
preferably within the range because the processability and
mechanical strength of the thermoplastic elastomer composition to
be obtained are improved.
[0191] Specific examples of the age inhibitor include hindered
phenol compounds, and aliphatic and aromatic hindered amine
compounds.
[0192] Specific examples of the antioxidant include butylated
hydroxytoluene (BHT) and butylated hydroxyanisole (BHA).
[0193] Specific examples of the pigment include: inorganic pigments
such as titanium dioxide, zinc oxide, ultramarine blue, blood red,
lithophone, lead, cadmium, iron, cobalt, aluminum, a hydrochloride,
and a sulfate; and organic pigments such as an azo pigment and a
copper phthalocyanine pigment.
[0194] Specific examples of the plasticizer include: derivatives of
benzoic acid, phthalic acid, trimellitic acid, pyromellitic acid,
adipic acid, sebacic acid, fumaric acid, maleic acid, itaconic
acid, and citric acid; and polyester, polyether, and epoxy
plasticizers.
[0195] Specific examples of the thixotropy imparting agent include
bentonite, silicic anhydride, a silicic acid derivative, and a urea
derivative.
[0196] Specific examples of the UV absorber include
2-hydroxybenzophenone, benzotriazole, and salicylate UV
absorbers.
[0197] Specific examples of the flame retardant include: phosphorus
flame retardants such as TCP; halogen flame retardants such as
chlorinated paraffin and perchlorpentacyclodecane; antimony flame
retardants such as antimony oxide; and aluminum hydroxide.
[0198] Specific examples of the solvent include: hydrocarbon
solvents such as hexane and toluene; halogenated hydrocarbon
solvents such as tetrachloromethane; ketone solvents such as
acetone and methyl ethyl ketone; ether solvents such as diethyl
ether and tetrahydrofuran; and ester solvents such as ethyl
acetate.
[0199] Specific examples of the surfactant (leveling agent) include
polybutyl acrylate, polydimethylsiloxane, a denatured silicone
compound, and a fluorine surfactant.
[0200] A specific example of the dehydrating agent includes
vinylsilane.
[0201] Specific examples of the rust inhibitor include zinc
phosphate, tannic acid derivatives, phosphates, basic sulfonates,
and various rust-proof pigments.
[0202] Specific examples of the adhesiveness imparting agent
include a conventionally known silane coupling agent, a silane
compound having an alkoxysilyl group, a titanium coupling agent,
and a zirconium coupling agent. More specific examples thereof
include trimethoxyvinylsilane, vinyltriethoxysilane,
vinyltris(2-methoxyethoxy)silane,
.gamma.-methacryloxypropyltrimethoxysilane, and
3-glycidoxypropyltrimethoxysilane.
[0203] General examples of the antistatic agent include: a
quaternary ammonium salt; and a hydrophilic compound such as
polyglycol or an ethylene oxide derivative.
[0204] The content of a plasticizer is preferably 0.1 to 50 parts
by mass, or more preferably 1 to 30 parts by mass with respect to
100 parts by mass of the thermoplastic elastomer. The total content
of the other additives is preferably 0.1 to 10 parts by mass, or
more preferably 1 to 5 parts by mass with respect to 100 parts by
mass of the thermoplastic elastomer.
[0205] The thermoplastic elastomer is self-crosslinkable in some
cases, but may be used in combination with a vulcanizer, a
vulcanization assistant, a vulcanization accelerator, a
vulcanization retardant, or the like as in the case of the
vulcanized rubber composition described above to the extent that
the effect of the present invention is not impaired.
[0206] A method of producing the thermoplastic elastomer
composition is not particularly limited, and an example of a
desirable method involves mixing the thermoplastic elastomer,
various additives that may be incorporated as required, and the
like by means of a roll, a kneader, an extruder, a universal
stirring machine, or the like.
[0207] Curing conditions under which the thermoplastic elastomer
composition is permanently crosslinked (by using a vulcanizer) can
be appropriately selected in accordance with various components to
be blended and the like, and are not particularly limited.
Preferable curing conditions include a temperature of 130 to
200.degree. C. and a time of 5 to 60 minutes.
[0208] The thermoplastic elastomer (composition) softens upon
heating to about 80 to 200.degree. C. as a result of the
dissociation of its three-dimensional crosslinkage (crosslinked
structure), whereby fluidity is imparted to the elastomer
(composition). This is probably because an intermolecular or
intramolecular interaction between side chains is weakened.
[0209] When the thermoplastic elastomer (composition) which has
softened and to which fluidity has been imparted is left at a
temperature of about 80.degree. C. or lower, the dissociated
three-dimensional crosslinkage (crosslinked structure) binds again
to cure the elastomer. The repetition of the above series of
operations causes the thermoplastic elastomer (composition) to
exert recycling property.
[0210] The use of such thermoplastic elastomer composition for the
adhesion between members each composed of a vulcanized rubber
composition is very useful because the facilitates the dimantling
of an adhesion portion to make it possible to maintain recycling
property and provides excellent adhesiveness.
EXAMPLES
[0211] Next, the present invention will be described more
specifically by way of examples. However, the present invention is
not limited to these examples.
[0212] <Preparation of Thermoplastic Elastomer
Composition>
[0213] 300.0 g of maleic anhydride-modified EPM (Toughmer MP0620,
ethylene content 70 mass %, manufactured by Mitsui Chemicals, Inc.)
were added to a press kneader heated to 190.degree. C., and were
masticated for 1 to 5 minutes. After that, 2.49 g (0.03 mol) of
3-amino-1,2,4-triazole were added, and the whole was kneaded for 20
minutes to prepare a thermoplastic elastomer A. The analysis of an
IR spectrum confirmed that the resultant thermoplastic elastomer A
was a polymer having a triazole ring introduced thereinto.
[0214] 10 parts by mass of carbon black (Seast V, manufactured by
Mitsubishi Chemical Corporation) were added to 100 parts by mass of
the resultant thermoplastic elastomer A, and the whole was
sufficiently kneaded by means of a banbury mixer until it became
uniform, to thereby prepare a thermoplastic elastomer composition
A.
[0215] <Preparation of Vulcanized Rubber Composition>
[0216] (1) Vulcanized Rubber Composition A
[0217] Carbon black (a filler), oil (a softener), zinc oxide (a
vulcanization assistant), stearic acid (a vulcanization assistant),
sulfur (a vulcanizer), and Nocceler (a vulcanization accelerator)
were added in compositions (parts by mass) shown in Table 1 below
to 100 parts by mass of EPDM, and the whole was uniformly dispersed
by means of a banbury mixer. EP 57 (ethylene content 56 mass %,
manufactured by JSR Co., Ltd.) was used for EPDM.
[0218] The resultant vulcanized rubber composition A was pressed
under heat at 200.degree. C. for 10 minutes (at a pressing pressure
of 2 MPa) to produce a vulcanized rubber sheet A (having a
thickness of 2 mm and a width of 25 mm). TABLE-US-00001 TABLE 1
Blend Trade name (manufacturer) Loading Carbon black Seast V
(manufactured by 100 Mitsubishi Chemical Corporation) Oil Process
oil (manufactured 50 by Showa Shell Sekiyu K.K.) Zinc oxide Zinc
oxide No. 3 5 (manufactured by Seido Chemical Industry Co., Ltd.)
Stearic acid Beads stearic acid 1 (manufactured by NOF CORPORATION)
Sulfur Oil-treated sulfur 1 (manufactured by Hosoi Chemical
Industry Co., Ltd.) Vulcanization Nocceler NS-P (manufactured 3.5
accelerator by OUCHISHINKO CHEMICAL INDUSTRIAL CO., LTD.)
[0219] (2) Vulcanized Rubber Composition B
[0220] A vulcanized rubber composition B and a vulcanized rubber
sheet B were produced in the same manner as that described above
except that EP 24 (ethylene content 49 mass %, manufactured by JSR
Co., Ltd.) was used for EPDM.
[0221] (3) Vulcanized Rubber Composition C
[0222] A vulcanized rubber composition C and a vulcanized rubber
sheet C were produced in the same manner as that described above
except that EP 27 (ethylene content 44 mass %, manufactured by JSR
Co., Ltd.) was used for EPDM.
Example 1
[0223] Two sheets of the resultant vulcanized rubber sheets A were
arranged on left and right sides so as to be symmetric with respect
to each other with a gap (5 mm) therebetween. The thermoplastic
elastomer composition A (3 mm in thickness) having the same width
as that of the gap was arranged to prepare a test piece having the
vulcanized rubber sheets A and the thermoplastic elastomer
composition A arranged in a row.
[0224] The test piece having the sheets and the composition
arranged in a row was pressed from above at 170.degree. C. for 5
minutes (at a presuring pressure of 2 MPa) to produce a sheet-like
vulcanized rubber molded product (having a thickness of 2 mm and a
width of 25 mm).
Comparative Example 1
[0225] A sheet-like vulcanized rubber molded product was produced
in the same manner as in Example 1 except that an unvulcanized EPDM
sheet (3 mm in thickness) was used instead of the thermoplastic
elastomer composition A.
[0226] Thus, a sheet-like vulcanized rubber molded product adhered
by means of EPDM which had been vulcanized (vulcanized EPDM)
instead of a thermoplastic elastomer was produced.
Comparative Example 2
[0227] A sheet-like vulcanized rubber molded product was produced
in the same manner as in Example 1 except that an IR thermoplastic
elastomer composition (an IR composition) was used instead of the
thermoplastic elastomer composition A.
[0228] The IR thermoplastic elastomer composition was produced
according to the following synthesis method. First, 300 g of Nipol
IR-2200 (manufactured by ZEON CORPORATION) and 50 g of maleic
anhydride were mixed by means of a press kneader at 210.degree. C.
for 40 minutes to synthesize a maleinized IR. 5.8 g (0.07 mol) of
3-amino-1,2,4-triazole were added to the IR, and the whole was
kneaded for 20 minutes to prepare an IR thermoplastic elastomer.
The analysis of an IR spectrum confirmed that the resultant IR
thermoplastic elastomer was a polymer having a triazole ring
introduced thereinto. 10 parts by mass of carbon black (Seast V,
manufactured by Mitsubishi Chemical Corporation) were added to 100
parts by mass of the resultant IR thermoplastic elastomer, and the
whole was sufficiently kneaded by means of a banbury mixer until it
became uniform, to thereby prepare the IR thermoplastic elastomer
composition.
<Breaking Strength>
[0229] Each of the resultant sheet-like vulcanized rubber molded
products was stamped into a #3 dumbbell-like test piece in such a
manner that the adhesive interface of the vulcanized rubber sheet A
would be the center of the dumbbell. A tensile test at a tension
speed of 50 mm/min was performed according to JIS K6251 to measure
a breaking strength (T.sub.B) [MPa] at room temperature (25.degree.
C.). Table 2 below shows the results.
[0230] In Table 2 below, the term "material break" means that the
thermoplastic elastomer composition A and the vulcanized EPDM used
for adhesion occurs cohesive failure, and the term "interfacial
break" means that the interface between the IR thermoplastic
elastomer composition and the vulcanized rubber sheet A broke.
<Recycling Property>
[0231] Each of the resultant sheet-like rubber molded products was
finely cut and subjected to press molding again. The number of
times a seamless and integrated sheet was produced was used for
evaluation on recycling property.
[0232] The case where such sheet was formed 10 or more times was
evaluated as ".largecircle." and the case where such sheet could
not be formed even once was evaluated as ".times.". Table 2 below
shows the results. TABLE-US-00002 TABLE 2 Comparative Comparative
Example 1 Example 1 Example 2 Adhesion portion Composition A
VulcanizedEPDM IR composition Breaking 1.5 3.1 0.2 strength
(Material (Material (Interfacial (Mpa) break) break) break)
Recycling .largecircle. X .largecircle. property
[0233] The results shown in Table 2 above revealed that the
adhesion of a vulcanized rubber composition using the thermoplastic
elastomer composition A showed a breaking adhesive force of 1 MPa
or more and had recycling property. The results also revealed that
the adhesion using vulcanized EPDM for an adhesion portion shown in
Comparative Example 1 showed a high breaking strength but had no
recycling property, and the adhesion using the IR thermoplastic
elastomer composition having no monomer unit forming a rubber
component of a vulcanized rubber composition shown in Comparative
Example 2 showed a remarkable reduction in breaking strength.
Examples 2 to 6 and Comparative Example 3
[0234] Next, a change in breaking strength due to a difference in
carbon black content between thermoplastic elastomer compositions
was examined.
[0235] Carbon black (Seast V, manufactured by Mitsubishi Chemical
Corporation) was fed in an amount (parts by mass) shown in Table 3
below to the thermoplastic elastomer A, and the whole was
sufficiently kneaded by means of a banbury mixer until it became
uniform, to thereby prepare a thermoplastic elastomer composition.
The thermoplastic elastomer composition prepared in Example 3 was
identical to the thermoplastic elastomer composition A prepared in
the foregoing.
[0236] Each of the resultant thermoplastic elastomer compositions
was evaluated for processability in accordance with the method
described below. Table 3 below shows the results.
<Processability>
[0237] Carbon black was fed into the thermoplastic elastomer A, and
the whole was kneaded by means of a banbury mixer. Whether the
elastomer and carbon black agglomerated to be of a massive form or
were of particle forms without agglomeration at the time of the
kneading was examined. As a result, as shown in Table 3 below, each
of Examples 2 to 6 was evaluated as ".largecircle." because the
elastomer and carbon black were of a massive form. Comparative
Example 3 was evaluated as "-" because carbon black was not
used.
[0238] Each of the resultant thermoplastic elastomer compositions
and the vulcanized rubber sheet produced in the foregoing were used
to produce a sheet-like vulcanized rubber molded product in the
same manner as in Example 1.
[0239] Each of the resultant sheet-like vulcanized rubber molded
products was evaluated for breaking strength and recycling property
by means of the methods described above. Table 3 below shows the
results. TABLE-US-00003 TABLE 3 Comparative Example 3 Example 2
Example 3 Example 4 Example 5 Example 6 Thermoplastic elastomer A
100 100 100 100 100 100 Carbon black 0 5 10 30 50 100
Processability .largecircle. .largecircle. .largecircle.
.largecircle. .smallcircle. .smallcircle. Breaking strength (Mpa)
0.7 1.2 1.5 2.0 2.4 3.4 Recycling property .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle.
[0240] The results shown in Table 3 above revealed that the
breaking strength can be increased by increasing the content of
carbon black to be comparable to that of the vulcanized rubber
composition produced in the foregoing.
Examples 7 to 9
[0241] Next, a change in breaking strength due to a difference in
ethylene content between a thermoplastic elastomer composition and
a vulcanized rubber composition was examined.
[0242] The thermoplastic elastomer composition A produced in the
foregoing was used as a thermoplastic elastomer composition.
[0243] Each of the vulcanized rubber compositions A to C (the
vulcanized rubber sheets A to C) produced in the foregoing was used
as a vulcanized rubber composition.
[0244] The resultant thermoplastic elastomer composition A and each
of the vulcanized rubber sheets A to C were used to produce a
sheet-like vulcanized rubber molded product in the same manner as
in Example 1. The sheet-like vulcanized rubber molded product
produced in Example 7 is identical to the sheet-like vulcanized
rubber molded product produced in Example 1.
[0245] The breaking strength of each of the resultant sheet-like
vulcanized rubber molded products was measured by means of the
method described above. Table 4 below shows the results.
TABLE-US-00004 TABLE 4 Example 7 Example 8 Example 9 Thermoplastic
elastomer 70 70 70 composition A Ethylene content (mass %)
Vulcanized rubber 56 composition A Ethylene content (mass %)
Vulcanized rubber 49 composition B Ethylene content (mass %)
Vulcanized rubber 40 composition C Ethylene content (mass %)
Difference in ethylene 14 21 26 content (mass %) Breaking strength
(Mpa) 1.5 1.1 0.9
[0246] The results shown in Table 4 above revealed that a
difference in ethylene content (mass %) of 25 mass % or less
provides a more excellent breaking strength.
Example 10
[0247] A state was held, in which two sheets of the resultant
vulcanized rubber sheets A were arranged on left and right sides so
as to be symmetric with respect to each other with a gap (3 mm)
therebetween. The gap was filled with the thermoplastic elastomer
composition A turned in a molten state by means of an injection
molding machine (J110ELIII, manufactured by NIPPON STEEL WORKS,
LTD.) at an injection pressure of 4 MPa. After the filling, the
resultant was cooled to room temperature while a pressure was
applied thereto, to thereby produce a sheet-like vulcanized rubber
molded product (having a thickness of 2 mm, a width of 25 mm, and a
length of 80 mm).
[0248] The resultant sheet-like vulcanized rubber molded product
was evaluated for breaking strength and recycling property by means
of the methods described above. Table 5 below shows the results.
TABLE-US-00005 TABLE 5 Example 10 Adhesion portion Composition A
Breaking strength 1.6 (Mpa) (Material break) Recycling property
.largecircle.
[0249] The results shown in Table 5 above revealed that even the
adhesion of a vulcanized rubber composition through injection using
the thermoplastic elastomer composition A shows a breaking adhesive
force of 1 MPa or more and has recycling property.
* * * * *